1. Field of the Invention
This invention relates to a pneumatically-driven tool. In one aspect, the invention relates to a device for the extraction of frictionally-fit fittings and tooling bits.
2. Description of the Related Art
Mechanical assemblies frequently utilize friction-fit components, such as fittings and tool bits, which must at times be separated. Friction pins, for example, can be used to hold two parts together. If the parts must be separated, the pin must first be removed. Generally, this is accomplished by repeatedly striking the pin with a hammer. Similarly, bearings are frequently press-fit into a housing. Removal of the bearing from the housing involves pulling or repeatedly striking the bearing until it is released. Other friction-fit or press-fit assemblies can occasionally require removal of the friction-fit or press-fit component from the remainder of the assembly.
A conventional way of removing a friction-fit or press-fit component is by rigidly attaching a pulling or pushing member to the component and applying a percussive force to the pulling member and thus to the component to be removed. The percussive force is developed by repeated striking of a heavy hammer against the member to progressively move the component out of its housing. The hammer is typically operated by hand. Consequently, the repetitive striking force can fatigue the operator and may even cause injury, particularly repetitive-motion injury.
Another means of removing a friction-fit or press-fit component is by use of a hydraulic puller comprising a hydraulic piston and cylinder assembly with a pulling member attached to the piston. The pulling member is attached to the object to be removed. The hydraulic cylinder assembly is attached to a stationary base, which is fixed with respect to the object. Hydraulic pressure is applied to the piston by a hydraulic pump, which causes the object to be removed from its housing. The hydraulic puller can comprise a relatively large assembly, which may be inconvenient or impractical for certain applications. As well, proper alignment of the device with the object to be removed may be difficult.
Yet another means is to utilize a screw-type puller in which a threaded pulling member is attached to the object and a mating threaded collar is turned against a base, gradually pulling the threaded rod and the removing attached object from the housing. As with the hydraulic puller, the screw-type puller can comprise a relatively large device having a base which must be properly aligned with the object to be removed in order to operate effectively.
The conventional pullers described above are frequently slow and require complicated assemblies which must be properly aligned with the object to be pulled and stabilized against the large pulling force that must be developed to remove the object. Human input is generally physically taxing. Shock to the various parts of the hands, arms and shoulders can cause fatigue and injury.